Placement of filter

[v1.5]

Hello there

First of all, I am thinking of providing protection for a sensitive card I have in my hand. this board works with 5v and requires about 1 amp current. This sensitive board include FPGA and some analog circuitry inside of it. For this board i want to make some protection via small external pcb of mine.

Its because needs 5v supply voltage i have thought that to use TPS25200 ic for this job. It is very convenient and includes many protection circuits. Also i want to add a second stage LC filter circuit of this external board for filtering dc power source noises which mosly from smps or wall adapter. But i don't know where to place this filter.

Should I place this filter after tps25200 or before? What do you think ? I'm little bit confused about it so do you have any advise for me ?

Thank you

 

[Nigel Goodwin]

If it's before, you're protecting the TPS25200 from the noise as well.

 

[v1.5]

Thanks .

So i m going to place that filter before the ic . What about the filter ? Is that filter good for smps or wall adapter voltage sources ? Is there any better and cost effective solutions for those kind of power sources output filter ? Or just second stage LC filter ok ?

 

[KeepItSimpleStupid]

Did you look an analog devices surge stopper products?

Your choice, I would consider transorbs or TVS diodes for the >20 volt spikes. (somewhat less).

The surge stoppers migh be better in reverse polarity and surge protection.

Don;t neglect ESD protection.